1. Field of the Invention
The present invention relates in general to receiver operation in satellite positioning systems (SATPS) such as the Global Positioning System (GPS), GLONASS, and the proposed Galileo system, and in particular to navigation processing for a SATPS receiver.
2. Description of the Related Art
Navigation processing for SATPS receivers usually comprises processing pseudoranges and Doppler frequency shift measurements to determine position and velocity of the receiver. However, this approach is sometimes unable to distinguish between alternate (valid and invalid) three-satellite solutions. Examples of such processing techniques are found in U.S. Pat. Nos. 5,416,712 by Geier, U.S. Pat. No. 5,883,595 by Colley, and U.S. Pat No. 5,590,043 by McBurney, all of which are incorporated by reference herein.